Armament and fire control system for helicopters



ARMAMENT AND FIRE CONTROL SYSTEM FOR HELICOPTERS Filed June 6. 1961 A ril 13, 1965 J. G. ALLEMANN 5 Sheets-Sheet 1 TRANS. GEAR BOX DRIVE INVENTOR. JAMES G. ALLEMANN April 13, 1965 J. G. ALLEMANN 3,177,862

ARMAMENT AND FIRE CONTROL SYSTEM FOR HELICOPTERS Filed June 6, 1961 5 Sheets-Sheet 2 INVENTOR. JAMES G. ALLEMANN J. G. ALLEMANN 3,177,862

ARMAMENT AND FIRE CONTROL SYSTEM FOR HELICOPTERS 5 Sheets-Sheet 3 a a H: A .w

A ril 13, 1965 Filed June 6, 1961 INVENTOR. JAMES G. ALLEMANN a n/ ATTORNEY April 13, 1965 J. G. ALLEMANN 3,177,862

ARMAMENT AND FIRE CONTROL SYSTEM FOR HELICOPTERS Filed June 6. 1961 5 Sheets-Sheet 4 IN VEN TOR.

50 I56 ZIQ 2/2 2 209 JAMES G. ALLEMANN BY F/g.8 g

" ATTORNEY April 13, 1965 J. G. ALLEMANN 3,177,862

ARMAMENT AND FIRE CONTROL SYSTEM FOR HELICOPTERS Filed June 6, 1961 5 Sheets-Sheet 5 28 V D.C.

Fig. [0

INVENTOR. JAMES G. ALLEMANN yzwm/ A 7'TORIVE Y United States Patent O 3,177,ss2 ARNAMENT AND IFKRE C(BNTRQL SYSTEM FGR HELICOPTERS James G. Allemann, 1723 W. 21st Sh, anta Ana, Calif. Filed June 6, 1961, Ser. No. 115,272 12 Claims. (6C3. l246) (Granted under Title 35, US. Code (1952), sec. 255

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to machine-gun type of armament, and more particularly to such armament for use on helicopters or the like wherein the centrifugal force of the rotor blades is utilized to impart the propelling force to the projectiles.

Conventional machine guns utilizing explosively propelled ammunition have been employed effectively for. many years and in various types of installations. Along with the outstanding advantages are some inherent disadvantages arising in the use of live ammunition employing explosives to impart the high muzzle velocity. These include safety considerations in stowage and handling the ammunition, complex ammunition feeding systems, cooling and recoil mechanisms, and frequent overhaul and maintenance problems. In primary combat vehicles, i.e. fighter aircraft, the advantages far outweigh the disadvantages. However, in some installations, i.e. helicopters, it is possible to utilize the available centrifugal force of the rotor assembly as the propelling force on the projectiles eliminating the need for live ammunition and, consequently, many of the aforementioned disadvantages. Although infantry-type machine guns have been designed in the art employing centrifugal force, such force was provided by prime movers, i.e. electric motors, etc. solely for this purpose.

In general, the invention utilizes the centrifugal force available in the propulsion system of a helicopter to propel projectiles to a target. By this means the helicopter can be readily provided with an offensive weapon for use in conjunction with the vertical envelopment concept of warfare, and as a protective aid in rescue operations which was not heretofore provided. This result is accomplished by incorporating firing barrels in the main rotor blades, the barrels being connected to a central hopper fed with round projectiles from a source in the helicopter. Mechanisms are provided for distributing the projectiles to the barrels, and selectively releasing a predetermined quantity thereof in the appropriate rotor blade barrel as it passes a firing station. A suitable cockpit control mechanism selects the time and duration of fire, and includes means for compensating for variations in rotor speed.

A principal object of this invention is to provide a helicopter with a simple and safe armament system having a high rate of fire.

Another object is to provide an armament for helicopters which utilizes the available centrifugal force created by the rotor blades as a means for projectile propulsion.

A further object is to provide a fire control mechanism for such an armament system.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a diagrammatic view of the invention employed on a helicopter for use as a saturation type of airto-ground Weapon system;

FIG. 2 is a diagrammatic top plan view of the helicopter disclosing the relationship of the rotor blades, the

Patented. Apr. 13, 1965 trajectory and fire pattern of the projectiles ejected by the novel armament system;

FIG. 3 is a top plan view of the projectile distributor feed pan with the cover partially cut away to show the projectile separators, feed tubes and gun barrels;

FIG. 4 is an enlarged-perspective view of a feed tube and feed pan bearing support;

,FIG. 5 is a longitudinal sectional view through one of said rotor blade barrels, with the blade removed, illustrating one type of projectile release mechanism;

FIG. 6 is a schematic view of a general arrangement of the drive and fire control selector components;

FIG. 7 is a cross-sectional view of the speed compensating mechanism and associated components;

FIG. 8 is an enlarged longitudinal cross-sectional View of the fire cont-r01 selector mechanism of FIG. 3;

FIG. 9 is a top plan view of the selector dial of FIG. 8 disposed 90 removed therefrom; and

FIG. 10 is a schematic wiring diagram of the electrical components.

Referring to the drawing where like reference numerals refer to identical parts throughout the figures there is shown in FIG. 1 one type of helicopter'12 on which the invention armament system 13 may be employed, the helicopter being known as a model HRZS. Such a helicopter has five rotor blades 14, with a rotor diameter of approximately 72 feet and a maximum rotor speed of 250 r.p.m. The invention system is particularly suited in conjunction with the vertical envelopment concept of warfare, and, accordingly, helicopter 1 2 is oriented in FIG. 1 to direct the projectiles in line of fire 15 downwardly toward a target, not shown, on surface 16 from the helicopter blades when in their forward lowermost rotational position.

, The pattern and angle of fire depicted in FIG. 2 is in a mode of operation wherein a volley of thirty longitudinally aligned projectiles (40 gauge, dimpled balls) are released in a volley from each blade in :a manner to be described later. The distance from point A to B indicates the degree of blade travel degrees) from the time the first projectile is released at the rotor hub until the first projectile leaves the rotor blade at point B. The line B-E represents the trajectory of the first projectile of the volley, the line CD represents the trajectory of the last projectile, while the distance D-E represents the width of tire pattern of the projectiles. Using the example heretofore described, it is possible with the invention system to fire 37,500 projectiles per minute, and at no time add more than 12 ounces of weight to the base of any blade at any one time.

Referring to FIGS. 35, there is shown a conicalshaped projectile distributor pan 20 formed .at a hub of rotor blades 18, each of the five blades 14 supporting a corresponding gun barrel 22 open to pan 20 at inlet 24 and extending preferably for the entire length of the blade. Pan 20 is mounted on the rotor head 25 and both are rotatably supported on a transmission drive shaft (not shown) located within transmission housing 28, the shaft being driven by a conventional helicopter engine, not shown, through lateral shafts 29'. Pan 20* rotates about a stationary central feed tube holder 26 (FIG. 4) by a ball-bearing assembly 27. As will be later described, transmission from the drive mechanism is also utilized in the fire control mechanism of the armament system. Holder 25 supports a plurality of'feed tubes 3%, seven being illustrated in FIG. 3,-which tubes are spaced around the holder and extend vertically through housing 28, through which projectile balls 31 from hoppers, not shown, conveniently located below in the helicopter passenger compartment are pneumatically or otherwise fed to distributor pan 20. Each upper tube end has a deflector lip 32 which guidesand evenly dise snweea tributes the respective falls outwardly in the pan where they are compartmentalized in a single layer by separators 34, one compartment for each barrel 22. Since the radial forces on the projectiles slightly exceed the tangential forces, the separators are suitably curved to relieve some of the radial force on the projectiles at gun barrel inlets 24.

The timed discharge of the projectiles from distributor pan 26 through each barrel 22 is controlled by an electrically-operated release mechanism 36 (FIG. as dictated by the fire-control selector mechanism to be described later with reference to FIGS. 6 and 7. In one embodiment referred to as option #2, the release mechanism comprises a firing lever 38 intermediately pivotally mounted by trunnion 40 to lugs 42 mounted on gun barrel 22. A coil spring 44 having ends bearing against barrel 2-2 and firing lever 38 biases the latter to a safe position shown in FIG. 5. Opposite ends of the firing lever are provided with forward and rearward tangs 46 and 4-7, respectively, adapted to project down through openings 48 in the gun barrel to block the passage of the projectiles therethrough. The length of the firing lever between the tangs accommodates 3t projectiles in the gun barrel which projectiles comprise the load that will be fired in any one volley from each rotor blade at each revolution. It is obvious that the length of the firing lever 38 can be redesigned to vary the number of projectiles in the volley. Movement of firing lever 38 is accomplished by a projectile release solenoid 5G pivotally hinged at 52 to pan 20, said solenoid having an armature 54 terminating in a clevis end 56 supported on an integral arm 39 of the firing lever. Solenoid 50 and the associated linkage is shown in a de-energized ceasefire position in FIG. 5. A safety feature is included in the linkage by forming the arms of the armature clevis with slots 58 slidably to receive a pin 59 anchored on firing lever arm 32 to create lost motion in the linkage and permit an emergency cease fire in the event release solenoid Si) is jammed in an energized condition. Solenoid 60 is pivotally mounted at 62 to clevis 56, the solenoid having an armature 64 pivoted at 66 to a locking latch 68 hinged at 76 to clevis 56. Solenoid 66 is shown in FIG. 5 in an energized condition which positions the free end of latch 68 to engage pin 59 and lock solenoid armature 54 positively to firing lever 38, permitting release of the projectile volley upon energization of release solenoid 50. In other words, both solenoids 5t) and 60 must be energized to permit firing of the projectiles. Deenergization of locking solenoid 60 permits pin 59 to ride in clevis arm slots 58 free of latch 68 and allows the firing lever to be pivoted to a cease-fire position regardless of the position of release solenoid 50. When firing lever 38 is pivoted from the position sown in FIG. 5 to the firing position, forward tang as is lifted from the first projectile, while rear tang 47 drops in front of the thirty-first projectile, permitting the thirty preceding pro ject-iles to be ejected by the centrifugal force on the respective rotor blade. Solenoid 59 is spring-loaded to the de-energized position illustrated, but, in the event it does not return to this position after firing, the force of spring 44, and the unrestricted travel allowed pin 59 in slots 58 by disengagement of latch 68, will return firing lever 38 to cease-fire position of FIG. 5.

As heretofore described, under firing option #2 (FIG. 5) a fixed number of projectiles are ejected, depending on the length of firing lever 38, from each gun barrel in the form of a volley and since the pattern is preset, the time of fire is the only variable that need be controlled. In the event it is desired that the number of projectiles ejected also be controlled, i.e. duration of fire, an option #1 can be provided by substituting a modified firing lever, not shown, in which tang 47 is removed. Suitable selector controls, later to be described, are provided for controlling both the time and duration of fire from a position in the cockpit.

FIG. 6 shows a general arrangement of a fire control selector mechanism 72 land a drive mechanism for driving the latter, including a transmission-adapter gear box 76 and a speed-compensating unit 78. Transmission gear box 76 (FIGS. 6 and 7) includes a master drive shaft 79 extending from the helicopter prime mover, not shown, box 76 providing two shaft outputs, one output being direct through splined connection 80 to a shaft 82, which may be flexible or rigid, to drive selector mechanism 72, and the second output being through a pair of beveled gears 83 to shaft 84- having a splined connection 86 to drive speed compensating unit 7 8..

Speed compensating unit 78 comprises three units shown in FIGS. 6 and 7, namely, a fiightweight assembly 68, a slaved hydraulic servo actuating system 90, and a solenoid bypass valve 92. Flyweight assembly 88 is contained in a housing 93 bolted to the transmission gear box, the housing being filled with oil through a cap 91 for dampening the rotating assembly. The assembly includes a carrier ring )4 integrally joined by a web 95 to a shaft 96 splined at 86 to transmission adaptor gear box shaft 84'. Radially spaced around and supported to ring 94 are a plurality of fiyweights 93, four being illustrated, mounted on the outside ends of arms 10%) in angular relation, which arms projects through and are intermediately pivoted in slots 102 in the carrier ring. The inner ends of the arms are rounded and lie under a collar 1% integral with a rod 196 of a hydraulic piston 108, the rounded ends of arms 1% providing a cam surface to bear against collar Hi4 and actuate the piston. Piston M8 is slidably disposed in a master cylinder 110, the latter being mounted to the flywheel assembly housing, forming end cylinder chambers 1112 and 114. The end chambers are connected by hydraulic lines 120 and 122, respectively, via solenoid valve 92 to corresponding end chambers 124 and 26 of a slave cylinder 123. Cylinder 128 houses a piston 13% having a piston rod 132 terminating in an integral rack gear 134 (see FIG. 6) adapted to provide a speed compensating mechanical input into the selector mechanism 72, as will be presently described. Servo cylinders 119 and 128 are provided with combination bleed valves and filler caps 133 located in both sets of cylinder chambers. Each piston is centered with the respective cylinders by a pair of oppositely disposed coil springs 135.

Solenoid valve 92 functions to cancel out any speed compensating corrections to the selector mechanism 72 that would normally occur during selection of the pattern and time of fire. The solenoid valve comprises a conventional solenoid 136 having an armature 133 reciprocable in a valve body 139 formed with two pairs of ports 14%) and 142 aligned with lines 120 and 122, respectively. The free end of armature 138 is formed as a spool valve and is provided with annular grooves 144 and 146, which in a tie-energized solenoid condition, as illustrated, aligns both sides of lines 120 and 12 2 to permit unrestricted servo flow between cylinders 111i} and 128. Armature 133 is constructed with a U-shaped internal passage 148, the armature moving by energization of the solenoid through selector mechanism 72 to block the flow from master cylinder and to bypass through passage 143 lines 12b and 122 to the servo cylinder 1228.

Operation of speed compensating mechanism 78 provides a correction input to selector control mechanism '72 to compensate for any variations in rotor blade speed that would otherwise cause an error in the pattern and/ or time of fire as determined by selector mechanism 72. Rotor blade movement transmitted through shaft 79 r0- tates fiyweight assembly 88. Any increase in rotor blade speed over an initial operating speed causes weights )3 to move further outwardly and downwardly by centrifugal force, the pivoting actions of fiyweight levers 1% moving piston M8 upwardly as viewed in FIG. 7. Such a piston movement displaces the hydraulic fluid in chamber 112 through line 129, via solenoid valve 92, to

chamber 124 of the slave cylinder causing piston 13d and rack gear 134 to move to the right as viewed in the figures. The effect of this movement on selector control mechanism '72 will be described shortly. The oil displaced in slave cylinder chamber 126 is ported in line 122 to chamber 114 of the master cylinder, A reverse movement of that described above occurs if 'rotor blade speed slackens below the set speed.

As heretofore described, the time of fire and the pattern of fire, depending on the selected option #1 or #2, and the operation of solenoid valve 92 is dependent upon the fire control selector mechanism 72 (FIGS. 6 and 8) mounted in the helicopter cockpit. Selector mechanism comprises four basic subassemblies, namely, a base and housing assembly 150, a cam-carrier ring assembly 152 rotatably supported on the housing assembly, a centrally disposed variable dwell cam drum assembly 154, and a selector dial assembly 156. Assembly 150 includes a base 158 supporting a housing 160 that includes a cylindrical intermediate portion 162, the latter terminating in an upper flange 164. Seated withinfiange 164 is an annular bearing 166 which rotatably supports a lower flange 1&7 of a cam follower carrier ring 168 of assembly 152. Carrier ring 168 is integrally formed at its lower end with 'a bevel gear 170 in driven engagement with a drive bevel gear 1'72 mounted on a carrier drive shaft 1'74 supported by bearings 176 on the housing walls. Drive shaft 174 terminates in a drive spline 178 for engagement with shaft 82 (FIG. 7) whereby the carrier ring is rotatably driven at the same speed as the rotor and blades.

The outer peripheral surface of carrier ring 168 is formed with six concentrically spaced contact races 180, the upper five of the races being electrically connected by conductors 182 to'corresponding cam follower arms 184, one arm being provided for each of the five rotor blades. The bottom race is electrically connected by a contact brush 186 supported on a leaf spring 187 which grounds the carrier ring assembly 152 to the housing. Associated with each of the five upper races, is a respective spring-backed brush 188 slidably mounted in a holder 190 to the housing, each brush being electrically connected by a conductor 192 in a circuit that controls release solenoids 50 and locking solenoids oil, to be described in reference with FIG. 10. The five cam follower arms 184 are identical in construction, and each comprise an arm extending through, and insulating therefrom, a drilled opening 194 in the carrier ring and intermediately pivoted therein on a horizontal pin 1%. Opening 124 may be outwardly flared to permit arm 184 to rock about pivot 196. The outer end of each arm 184 is provided with an electrical contact'198 adapted to engage a contact 200 on a fixed arm 262 supported by and grounded to carrier ring 186. The pivotal movement of the cam follower arms about a horizontal axis to make and break electrical contact is controlled by the variable dwell cam drum assembly154 presently to be described. 7

Assembly 154 comprises a lower cam unit comprising a half-drum 204 having an upper cam surface including a recessed portion 205 and a raised lobe portion 206, said drum being integrally mounted on the top of a central spindle 26 8. The base of spindle 2118 fits in a socket 209 of a pinion base gear 210 and secured therein by a retainer and friction ring 211, gear 210 being supported by a bearing 212 on a vertical stub shaft 214 secured to housing base 153. As heretofore described, gear 210 is rotated by rack gear 134 of speed compensating unit 78 whenever a change of rotor speed occurs to change the relation between the cam lobe and the cam follower arms 184 to readjust the time of the fire accordingly.

Associated with the lower cam unit, is an upper cam unit comprising a half-drum 216 having a lower cam surface including a recessed portion 217 and a depending (5 lobe portion 218. the respective opposing cam surfaces of the drums 204 and 216 are disposed in mating relation, being spaced apart to form a curved circular path for cam follower arms 184. The arcuate length of the depending lobe portion 218 determines the fixed duration of fire under option #2, and the rotational position of the drums with respect to the cam follower arms determines the time of fire as modified by the speed compensating unit. Under option #1 the length of the lobe portion 218 represents the minimum duration of fire, with provision for increasing the duration of fire by increasing the length of fixed lobe 218 through adjustable cam lobes as will be later described. The drums are maintained in their spaced relation by three spaced vertical attaching rods 22% secured at their upper ends inside upper drum 216 and projecting freely through apertures 222 in lower drum 204 and fastened at their lower ends to respective horizontal attaching rods 224. Horizontal rods 224 extend radially, the inner ends being inset in a main vertical shaft 226, and the outer ends of the horizontal rods are secured to a safe lock collar 223. Collar 228 is concentrically arranged outwardly and closely adjacent lower drum 204. Shaft 226 is slidably mounted in a spindle recess 2-29, and lifting shaft 225 by its knob 234 raises the upper edge 232 of the lock collar to a position where it pivots all five inner ends of follower arms upward to break the electrical engagement of contacts 198 and 200. The upper cam unit is simultaneously raised by shaft 226 through rods 224 and 226 to allow for this movement of the cam follower arms. Annular grooves 234 in shaft 226 are adapted to be engaged by ball detent 236 in the spindle to retain the shaft in either of the two selected vertical positions.

Operation of the safe lock collar by lifting knob 230 simultaneously energizes a bypass switch 238 mounted by a bracket 241) to the inside wall of housing 150, the switch being connected by conductors 24-2 to bypass solenoid 92 of the speed compensating unit in FIGS. 6 and 7. Switch 238 includes a pair of contacts 243 electrically connected to conductors 242 and adapted to be bridged by a slidable contact 244 on an arm246 in rolling contact within a slot 248 in a lower extension 259 of safe lock collar 228. Extension 25th is arcuate and slot 248 is of sufficient length to permit rotation of spindle 208 throughout the adjustment'by the speed compensating mechanism and time of fire selection. Accordingly, lifting knob 23% closes bypass switch 238 to energize solenoid 136 (FIG 7) which positions solenoid armature 138 to block the hydraulic flow in lines and 122, allowing base gear 211 and the cam drum assembly "154 to be returned to neutral positon by centering springs of slave cylinder 128. Thus, the pattern of fire under option #1 should always be made with knob 23%) lifted in the up position.

Selector dial assembly 156, the fourth basic subassembly of fire control selector mechanism '72, includes shaft 226 axially movable by knob 23% as previously described, and a mechanism for selecting the time of fire and the pattern of fire, the latter used only when firing option #1 is employed. Such mechanism includes an outer hollow shaft 252 concentrically mounted and rotatable about shaft 226, outer shaft 252 being based in a sleeve 254, rotatably supported on lower drum 204 through a retaining friction ring 256. Sleeve 254 is longitudinally slotted at 258 to receive a pin 259 on outer shaft 252 to permit independent axial movement of the shafts, but common rotation of the sleeve and the outer shaft through an upper selector tab 269. A pair of adjustable cam lobes 2&2 and 264 are supported in concentric relation with fixed length lobes 206 and 218 by arms 266 and 268 integral with outer shaft 252 and sleeve 254, respectively. By making a selection of duration of 'fire (option #1) through manipulating tab 260, outer shaft 252 and sleeve 254 rotate the adjustable lobes to extend The recessed and lobe portions of Z or shorten the over-all length of the cam lobes and thereby change the relation of the cam lobes to the cam followers (FIGS. 6 and 8). Friction ring 256 is designed with a lesser frictional force than the frictional force of friction ring 211 on spindle 208 so that selection by tab 250 will not disturb the position of cam assembly 154.

Indication of the selection of tab 260 and knob 230 is accomplished by an outer dial 270 formed on an annular face of housing 160 (see FIG. 9), and a pair of disc segments 272 and 274 concentrically arranged within a housing recess 275 and rotatable about the axis of shaft 226. Disc 272 extends for an arc of approximately 270 and is provided with an integral hub portion 277, locked by set screw 278 to both central shaft 226 and knob 230, disc 272 being provided with an arcuate slot 280 through which selector tab 260 projects and is free to move. Duration of fire disc 274 extends for about a 90 arc and is supported by a collar 282 slidably disposed about hub 277. Disc 274 is movable by a tang 284 having a free end anchored therein and diametrically connected to tab 260 by an integral hub 2% locked by screw 288 to outer shaft 252. Dial 270 comprises three concentric indicia scales representing helicopter altitudes of 300', 400' and 500, and scales of width of pattern in feet per square being 20', 30' and 40, respectively. The area 200 between the edges of disc segments 272 and 274 represents the fixed pattern of firing when employing option #2, and is readily determined by extending the edges of discs to the scales. The pattern of fire may be selected at any position around the dial face by rotating selector knob 156 causing the discs to move together in the same relative position. When option #1 is employed (to increase the duration of fire beyond that fixed selection obtainable with option #2) knob 230 is lifted in the up position, and tab 260 is actuated to change the relation of disc segment 274 with disc segment 2.72, and which, as heretofore described, rotates adjustable cam lobes 262 and 265 to vary the total length of cam lobe surface 218, and, accordingly, the duration of fire.

FIG. 10 shows a circuit diagram for controlling the sequential operation of the various components and includes an electrical source of power 292, which may be the conventional aircraft 28 volt D.C. source, a master armament switch 294 and a trigger firing switch 2% connected in series through conductor 298, the trigger switch usually being located on the pilot control stick. Conductor 298 is connected to a common side of a coil 300 of a relay 302, one relay being provided for each of the projectile barrels on the five helicopter rotor blades. Since the electrical components for each gun barrel are identical, the description of one set of components will suffice. The

other side of each relay coil is electrically connected by line 192 to one of the spring-backed brushes 188 which engages a corresponding race 100, of the carrier ring assembly 152 (FIG. 8). Each race 180 in turn is connected by conductor 182 to cam follower arm 184 on which is attached contact 198 adapted to engage contact 200 grounded to the housing by arm 202, bottom race 180, and leaf spring 187.

Relay 302 is provided two pair of spaced contacts upper and lower contacts 304 and 306, as appears in the drawing, and a pair of switch arms 305 and 307, respectively, mounted on coil armature 308 that is spring biased in a downward direction by coil spring 310. Switch arm 307 is fixed on armature 308, whereas upper switch arm 305 is slidably mounted on the armature and is biased to a lowermost position by spring 310 where it is closest to its contacts 304 than is lower switch arm 307 to its contacts 306. One side of contacts 304 and 306 is connected by conductor 307 to a point between switches 294 and 296 through a master armament switch relay 309. The other side of contact 304- is connected by conductor 312 to locking solenoid 60, while contacts 306 are connected by conductor 314 to release solenoid 50 (see FIG. the other end of each solenoid being grounded. The armatures of firing solenoids'50 in FIG. 10 are illustrated oriented in different radial directions to simulate the position of the respective helicopter blades. The contacts and arms are so arranged that when relay 302 is energized through the closing of the respective cam follower switch, upper switch arm 305 bridges contacts 304 to energize locking solenoid 60 just before lower switch arm 307 closes contacts 305 to energize release solenoid 50 to initiate the firing of the projectiles through the respective helicopter blade. The de-energization of relay 302, by the cam follower arm 184 riding ofi cam lobe surface 213 de-energizes release solenoid 50, and then solenoid 60 shortly thereafter. Firing lever 38 is pivoted to the cease-fire position by the return spring of release solenoid 50 and return spring 44, the latter being able to return firing lever 38 to the cease-fire condition by itself in the event of the malfunction of solenoid 50. Thus, it is apparent that firing occurs when the relay 302 of the corresponding helicopter blade is energized, the other four relays 302 being de-energized to prevent firing in their respective blades, subsequent firing occuring in sequential order as each blade reaches the firing position as determined by cam carrier assembly 154. For purpose of illustration, the uppermost'relay 302 is shown in an energized condition to permit firing in its respective rotor blade, the remaining relays of the other four rotor blades being de-energized.

Bypass solenoid 136 is connected by conductor 316 to the power source through a relay 318 controlled by its coil energized by bypass slide switch 238 through relay 309 whenever knob 230 is lifted to establish a safe position of the control mechanism.

Operation of the armament system can best be described with reference to FIG. 6. Assuming that firing occurs under option #2, that is, a fixed number of projectiles, i.e. thirty, are released through each helicopter blade as it reaches the firing position. The operator selects the time of fire by rotating knob 230 which positions cam dwell assembly 154, according to the sector shown on outer dial 270. The width of the pattern between segrnent discs 272 and 274 on the indicator dial assembly remains constant under option #2, and is illustrated in FIG. 2.

Cam carrier ring assembly 152 is driven about the cam drum assembly in the direction of the arrow in FIG. 6 at a speed synchronized with the rotor blades by bevel car 172 through shaft 82 from the transmission gear box 76. As each cam follower arm 184 rides down on depending cam lobe 218 it closes contacts 198 and 200 and the respective firing or release solenoid 50 is energized allowing the release of the projectiles in the corresponding rotor blade barrel. As each cam follower arm 184 rides off cam lobe 218 the contacts are opened de-energizing its release solenoid 50 to allow firing lever 38 of the respective blade to return to the cease-fire positions. Cam lobe 218 is of sufiicient length to allow all thirty projectiles be ween firing lever tangs 46 and 47 to be discharged through gun barrel 22 before the cam follower arm rides off the cam lobe to de-energize firing solenoid 50. Each cam follower arm 184 for the respective helicopter blade as it reaches the firing position, in succession, rides on the cam lobe 218 to effect the firing action.

With a helicopter rotor speed of 250 r.p.m., it is possible to fire a total of 37,500 forty-gauge projectiles a minute, at a muzzle velocity of approximately 1,060 f.p.s., and at no time add more than 12 ounces of weight to the base of any blade at any one time.

Any change in rotor speed above or below 250 r.p.m. that would otherwise affect the time of fire is accommodated by speed compensating unit 76 wherein energy is imparted by flyweight 98 through hydraulic servo system to drive pinion base gear 210 through rack gear 134 to rotate the cam drum assembly 154 and therefore change the relation of cam lobe 218 to the cam follower arms 184 to readjust the time of fire accordingly. Speed compensation need occur only after the time of fire is selected and bypass switch 238 is open by depression of knob 230. However, selection of a change of fire (or a change in pattern under option #1) is possible without interference by the speed compensating unit by lifting knob 230 which closes switch 238 and energizes solenoid 136 (providing master armament switch 294 is closed) to bypass the servo system 90 enabling the neutralizing of any speed compensation by the centering of slave cylinder 128.

In the event of firing under option #1, it is desired to increase the duration of fire beyond the fixed number of projectiles available under option #2, selector tab 260 is actuated to bring into operation the adjustable cam lobes 262 and 264 which increase the total length of the fixed cam lobe 218 and therefore increase the time that the respective firing solenoids 50 are energized. Of course,

under option #1 firing lever 38 must be modified by elimination of tang 47 or otherwise, to permit the increased number of projectiles to be discharged.

Accordingly, the present invention provides an offensive weapons system particularly suited for helicopters wherein the centrifugal force generated by the rotor blades is utilized to impart the propelling force on the nonexplosive projectiles. By means of a unique feeding and distribution system, the round projectiles are fed from a hopper within the helicopter upwardly through the rotor to feed the gun barrels mounted on the rotor blades. Provision is made to fire a fixed number of projectiles (option #2) or a variable number of projectiles (option #1) by a fire control selector mechanism conveniently located to the pilot in the helicopter, and having the necessary firing safety provisions. The time of firing can be varied to cover any selected sector around the helicopter. The present system provides gerater fire power than conventional aircraft armament systems with less complexity.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

1. In combination with a helicopter having a rotor, a plurality of radially extending rotor blades supported by the rotor, a rapid-fire armament system comprising a projectile barrel supported on and extending the length of each blade, a supply of ball-type projectiles located within said helicopter, a pan mounted on said rotor for distributing projectiles to each of said barrels, feed tubes extending from the projectile supply through the rotor to the pan, fluid means for transporting the projectiles through said feed tubes, a solenoid supported on said rotor adjacent each of said barrels, a projectile release linkage operated by said solenoid to regulate the fiow of projectiles through the barrel, a mechanism for controlling the release of said projectiles when the rotor blades reach a preselected firing position said control mechanism including a switch for each barrel, said switch connected to a corresponding solenoid, means for actuating said switches in a predetermined sequence during rotation of the rotor to release said projectiles at said firing position of said rotor blades.

2. The apparatus of claim 1 wherein said last-mentioned means is adjustable to enable the firing position of said blades to be varied.

3. The apparatus of claim 2 wherein said means is operable to actuate all of said switches to a safe position preventing any projectile discharge.

4. In combination with a helicopter having a rotor, a plurality of radially extending rotor blades supported by the rotor, a rapid-fire armament system comprising a fire control selector mechanism, a housing, a rotatable ring supported on the housing and having an axis of rotation, means for driving the ring at a speed corresponding to the rotor speed, a cam drum assembly disposed in concentric spaced relation within said ring and supported on a spindle, means for rotating said spindle, said assembly having a drum formed with a cam surface a portion of which surface is raised, a plurality of switches supported on the ring at spaced positions thereabout, one switch for each rotor blade, each switch including a pivotal arm having at one end a cam follower for engaging the cam surface, said ring being provided with a plurality of electrical slipring contacts, means for electrically connecting each switch to a respective slip-ring contact, a sleeve mounted concentric with said cam drum assembly, and means for displacing said sleeve axially the drum to actuate all of said cam followers and inactivate the respective switches.

5. The combination of claim 4 wherein the housing supports a bypass switch which is actuated by the movement of said sleeve.

6. In combination with a helicopter having a rotor, a plurality of radially extending rotor blades supported by said rotor in a plane substantially parallel to a plane containing the longitudinal axis of the helicopter fuselage, a rapid-fire armament system comprising projectile barrels supported on a plurality of said blades, a supply of balltype projectiles located at a position below said rotor blades, a projectile distribution means for feeding said balls from said supply upwardly to separate ones of said barrels, and means for selectively releasing a plurality of said projectiles for ejection through said barrels by the centrifugal force exerted by said blades at a predetermined time, said releasing means adapted to restrain and then release a plurality of projectiles in each barrel so that the projectiles may be fired in a volley whereby a preselected firing pattern is achieved.

7. In combination with a helicopter having a rotor, a plurality of radially extending rotor blades supported by the rotor in a plane substantially parallel to a plane containing the longitudinal axis of the helicopter fuselage, a rapid-fire armament system comprising a projectile barrel supported on each blade, a supply of ball-type projectiles located within said helicopter beneath said rotor blades, pneumatic means for feeding said projectiles from said supply through said rotor to said barrels, means for selectively releasing a plurality of said projectiles through said barrels, said releasing means adapted to restrain and then release a plurality of projectiles in each respective barrel so that the projectiles may be fired in a volley, and means for controlling the release of said restrained projectiles at a predetermined rotational position of each blade whereby a preselected firing pattern of the projectiles is achieved.

8. The apparatus of claim 7 wherein said feeding means includes a pan of a size to be capable of storing a plurality of projectiles in laterally disposed relation in a plane containing the barrels, said pan having guide means for each barrel for directing the projectiles to the respective barrels.

9. In combination with a helicopter having a rotor, a plurality of radially extending rotor blades supported by the rotor in a plane substantially parallel to a plane containing the longitudinal axis of the helicopter fuselage, a rapid-fire armament system comprising a projectile barrel supported on each blade, a supply of ball-type projectiles located Within said helicopter beneath said rotor blades, pneumatic means for feeding said projectiles from said supply through said rotor to said barrels, releasing means for selectively releasing said projectiles through each of said barrels, said releasing means including a solenoid, a pivotal arm connected by linkage to said solenoid to be actuated thereby, said arm having a tang adapted to be movable into and out of an opening in the respective barrel upon pivoting of said arm to block and release the projectiles, respectively, said releasing means adapted to restrain a plurality of projectiles in each respective barrel so that the projectiles may be fired in a volley, and means for controlling the release of said restrained projectiles at a predetermined rotational position 11 of each blade whereby a preselected firing pattern of the projectiles is achieved.

10. The apparatus of claim 9 wherein means are provided in said linkage for permitting limited movement of the pivot arm relative to the solenoid to establish an emergency cease fire condition in the event that the solenoid is jammed in a firing position, and means are provided for canceling said limited movement.

11. In combination with a helicopter having a rotor, a plurality of radially extending rotor blades supported by the rotor in a plane substantially parallel to a plane containing the longitudinal axis of the helicopter fuselage, a rapid-fire armament system comprising a projectile barrel supported on each blade, a supply of ball-type projectiles located within said helicopter beneath said rotor blades, pneumatic means for feeding said projectiles from said supply through said barrels, means for selectively releasing said projectiles through said barrels, said releasing means adapted to restrain a plurality of projectiles in each respective barrel for firing the projectiles in a volley, and 20 means for controlling the release of said projectiles at a predetermined rotational position of each blade, said controlling means including a cam follower member and a cam member, one of said members being rotatable at a speed proportional to the speed of said rotor blades, the time of firing of said projectiles being a function of the length of the cam whereby a preselected firing pattern of the projectiles is achieved.

12. The apparatus of claim 11 wherein compensating means are provided for variations in the rotor blade speed, and the other of said members being positionable by said compensating means to readjust the time of firing.

References Cited by the Examiner UNITED STATES PATENTS 1,289,895 12/18 Pewther 124--6 1,472,080 10/23 McNaier 1246 2,848,569 8/58 Moss et a1. 20027 2,920,152 1/60 Werner 200-27 RICHARD C. PINKHAM, Primary Examiner.

LOUIS R. PRINCE, DELBERT B. LOWE, ARTHUR M. HORTON, Examiners. 

6. IN COMBINATION WITH A HELICOPTER HAVING A ROTOR, A PLURALITY OF RADIALLY EXTENDING ROTOR BLADES SUPPORTED BY SAID ROTOR IN A PLANE SUBSTANTIALLY PARALLEL TO A PLANE CONTAINING THE LONGITUDINAL AXIS OF THE HELICOPTER FUSELAGE, A RAPID-FIRE ARMAMENT SYSTEM COMPRISING PROJECTILE BARRELS SUPPORTED ON A PLURALITY OF SAID BLADES, A SUPPLY OF BALLTYPE PROJECTILES LOCATED AT A POSITION BELOW SAID ROTOR BLADES, A PROJECTILE DISTRIBUTION MEANS FOR FEEDING SAID BALLS FROM SAID SUPPLY UPWARDLY TO SEPARATE ONES OF SAID BARRELS, AND MEANS FOR SELECTIVELY RELEASING A PLURALITY OF SAID PROJECTILES FOR EJECTION THROUGH SAID BARRELS BY THJE CENTRIFUGAL FORCE EXERTED BY SAID BLADES AT A PREDETERMINED TIME, SAID RELEASING MEANS ADAPTED TO RESTRAIN AND THEN RELEASE A PLURALITY OF PROJECTILES IN EACH BARREL SO THAT THE PROJECTILES MAY BE FIRED IN A VOLLEY WHEREBY A PRESELECTED FIRING PATTERN IS ACHIEVED. 